import { useContext } from "react"; 
import { ThemeContext } from "../../ThemeContext";
// use
// 函数
// 响应式状态和生命周期 
// 很好用
const Child = () =>{
    const theme = useContext(ThemeContext);
    return(
        <div className = {theme}>
            Child {theme}
        </div>
    )
}